Compositions of various types have incorporated within them components which provide cooling sensation to mucosal membranes and/or to skin. Such compositions include toothpastes, mouthwashes, perfumes, lotions, shaving cream, post shaving preparations, shampoos, antiperspirants, deodorants, beverages, chewing gum, tobacco products, and pharmaceutical products among many others.
It is well established that the "cooling" effect of menthol is a physiological effect due to the direct action of menthol on the nerve endings of the human body responsive for the detection of hot or cold and is not due to latent heat of evaporation. It is believed that the menthol acts as a direct stimulus on the cold receptors at the nerve endings which in turn stimulate the central nervous system.
Although menthol is well established as a physiological coolant its use alone, in some compositions, is limited by its strong minty odor and its relative volatility.
Several other compounds have been reported in the technical literature as having an odor or flavor similar to menthol and from time to time have been proposed as flavorants or odorants in a variety of topical and ingestible compositions. For example, Japanese Patent Publication No. 39-19627 reports that 3-hydroxymethyl p-menthane (menthyl carbinol) has a flavor closely resembling that of 1-menthol and suggests its use as a flavorant in confectionary, chewing gum and tobacco. In Swiss Patent No. 484,032 certain saccharide esters of menthol are proposed as additive to tobacco. In French Pat. Spec. No. 1,572,332 N,N-Dimethyl 2-ethylbutanamide is reported as having a minty odor and refreshing effect, and the minty odor of N,N-diethyl 2,2-dimethylpropanamide is referred to. A similar effect is reported for N,N-diethyl 2-ethylbutanamide in Berichte 39, 1223, (1906). A minty odor has also been reported for 2,4,6-trimethylheptan-4-ol and 2,4,6-trimethyl help-2-en-4-ol in Parfums-Cosmetiques-Savons, May 1956, pp. 17-20. The cooling effect of menthol and other related terpene alcohols and their derivatives has also been studied and reported in Koryo, 95, (1970), pp. 39-43. 2,3-p-menthane diol has also been reported as having a sharp cooling taste (Bellstein, Handbuch der Organischen Chemie, 4th Ed. (1923) Vol. 6, p. 744).
Carboxamides have also been disclosed for use in a variety of compositions. Two patents describing such materials and compositions are U.S. Pat. No. 4,136,163, Jan. 23, 1979 to Watson et al. and U.S. Pat. No. 4,230,688, Oct. 28, 1980 to Rowsell et al. These patents as well as those set forth above are incorporated herein in their entirety by reference.
Although there have been these significant efforts to provide enhanced cooling properties to a wide variety of products there is still the need to provide improved performance.
It is an object therefore of the present invention to provide improved coolant compositions.
It is a further object to provide improved coolant compositions comprising a ketal material and a second coolant agent.
It is a further object of the present invention to provide improved coolant compositions comprising a ketal and a carboxamide or menthol or mixtures thereof.
These and other objects of the present invention are described in detail below.
All measurements referred to herein are made at 25.degree. C. and all percentages are by weight unless otherwise specified.